1. Field of the Invention
The present invention relates to the display field, and more particularly to a liquid crystal display (LCD), a flat display and a gate driving method thereof.
2. Description of the Related Art
For reducing costs of display panels, many technologies are developed for saving peripheral ICs (integrated circuits) of the panels, wherein a HSD (half source driver) technology is widely applied. FIG. 1 is a schematic view of a panel cooperating with the HSD technology. As shown in FIG. 1, the panel includes a plurality of gate lines (such as, those indicated by labels G1˜Gm), a plurality of source lines (such as, those indicated by labels S1˜Sn), a plurality of transistors 102 and a plurality of pixels 104. m and n are both natural numbers. From a mode of coupling pixels as shown in FIG. 1 it can be seen that, the pixels in the same row are coupled to two different gate lines respectively.
FIG. 2 is a time sequence chart of conventional gate driving pulses which are adapted into the panel as shown in FIG. 1. Referring to FIG. 2, each of the gate driving pulses (such as those indicated by a label 202) is configured for turning on the corresponding pixels, thus the turned-on pixels are charged to load corresponding data voltages therein for displaying a desired image. However, since displays are developed for obtaining a high resolution and a high image quality, a width of the gate driving pulses must be shortened correspondingly for being gradually compressed to be a period for charging the pixels. Thus the conventional driving technology as shown in FIG. 2 is poor for charging the pixels. Therefore a pre-charge driving technology is developed, which is shown in FIG. 3.
FIG. 3 is another time sequence chart of conventional gate driving pulses. Referring to FIG. 3, the pre-charge driving technology increases the width of the gate driving pulses, and make two adjacent gate driving pulses partially overlap. Since the width thereof is increased, the novel driving technology has a better capability for charging the pixels than the above conventional driving technology. However, the novel driving technology will make two adjacent pixels in the same pixel row have different luminance, thus it will degrade the quality of the display images, which will be described in FIG. 4.
FIG. 4 is a schematic view for describing faults of the technology as shown in FIG. 3. Gate lines Gk and Gk+1, source lines Sj and Sj+1, transistors 406 and 416, and pixels 408 and 414 are shown in FIG. 4. k and j are both natural numbers. In addition, parasitic capacitances 410, 412, 418 and 420 are also shown in FIG. 4. Labels 402 and 404 represent gate driving pulses provided to the gate lines Gk and Gk+1 respectively. As shown in FIG. 4, In an enable period of the gate driving pulse 402, the gate driving pulse 404 is transmitted to the gate line Gk+1 for turning on the pixel 414. When the pixels 408 and 414 are turned on, the two pixels are loaded corresponding data voltages respectively. However, the data voltage loaded in the pixel 408 is influenced by the coupling effect of the parasitic capacitances, and the data voltage loaded in the pixel 414 is also influenced by the coupling effect of the parasitic capacitances, which will be described in detail in following.
When the enable period of the gate driving pulse 402 is ended, the electric potential of the gate line Gk is transferred from a high potential to a low potential, thus the gate line Gk pulls down the data voltage loaded in the pixel 408 by the coupling effect of the parasitic capacitance 410. Then the enable period of the gate driving pulse 404 is ended subsequently, the electric potential of the gate line Gk+1 is transferred from the high potential to the low potential, thus the gate line Gk+1 pulls down the data voltage loaded in the pixel 414 by the coupling effect of the parasitic capacitance 420, and the gate line Gk+1 also pulls down the data voltage loaded in the pixel 408 again by the coupling effect of the parasitic capacitance 412. Therefore when displaying an image, the numbers of pulling down the data voltages loaded in the pixels 408 and 414 are different, thus the luminance of the two pixels are different.